According to the 1988 National Survey of Family Growth, 2.3 million U.S. women aged 15-44 have impaired fertility. The number who seek and receive treatments for infertility is rapidly increasing. Recent case reports note the occurrence of ovarian cancer among infertile women receiving ovulation induction medications. Case-control studies have found an increased risk of ovarian cancer among women with involuntary infertility. The observed associations have been weak, but these studies included few infertile women and had extremely limited information about the nature of their infertility. This overall weak association may be due to much stronger risks in some subset of infertile women; those with anovulatory infertility especially deserve study. A study designed to disentangle the association between anovulatory infertility, its treatments, and ovarian cancer is necessary to elucidate the pathogenesis of this cancer. An historical cohort study will be the quickest and most powerful way to delineate precisely these relationships. Such a study will also allow the assessment of other health outcomes that may occur among infertile women. Because assembling this cohort will be complex, time consuming, and costly, we propose a pilot study to evaluate its feasibility. During this 12 month pilot, we will accomplish the following tasks: 1) enumerate and abstract clinical records of women evaluated and treated in a single infertility practice from 1965 until 1974, 2) classify these women according to type of infertility and treatment received, 3) trace these women and determine their willingness to participate in a follow-up study, and 4) accomplish these same tasks for a sample of patients from ten additional practices that each included thousands of infertile women during these years. The quality of the clinical data, the numbers of potential subjects identified, and the tracing rates that are achieved in this sample will determine if the performance of a large historical cohort study can be justified.